The atomic force microscope has been an essential tool in the past few years for visualization of mesoscopic structures, and has been applied to numerous examples in biological systems. The finite size of the probe tip, however, means that the picture produced by the AFM inevitably includes the tip geometry convoluted with the desired image of the sample. If the tip is asymmetric and/or deformed, the resulting image may bear little resemblance to the original sample. Even in the case of a “good tip”, however, the effect on the image is non-negligible, causing broadening and obscuring of features. In this presentation, approaches developed in our laboratory with regards to problems in imaging mesoscopic samples will be discussed.
In samples where the primary tip-sample interaction is via excluded volume - that is, the tip and sample are mutually impenetrable and come into contact - we had been utilizing a numerical algorithm for removing the tip geometry from the AFM image.